CN113906110A

CN113906110A - Aqueous ink for inkjet recording and inkjet recording apparatus

Info

Publication number: CN113906110A
Application number: CN202080040479.5A
Authority: CN
Inventors: 栗木宽文; 东山俊一; 永野太郎
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2019-05-31
Filing date: 2020-03-24
Publication date: 2022-01-07
Also published as: EP3976719A1; US20220112389A1; WO2020241019A1; EP3976719B1; JP7392292B2; JP2020196779A

Abstract

An aqueous ink for inkjet recording, comprising: a liquid component that is liquid at 20 ℃; and a solid component which is solid at 20 ℃. The liquid component comprises: a first water-soluble organic solvent having a vapor pressure of not less than 7Pa at 20 ℃; a second water-soluble organic solvent having a vapor pressure of not more than 1Pa at 20 ℃; and water. The solid component comprises at least one resin selected from: acrylic resins, maleic ester resins, vinyl acetate resins, carbonate resins, styrene resins, vinyl resins, propylene resins, polyurethane resins, vinyl chloride resins, and copolymer resins thereof.

Description

Aqueous ink for inkjet recording and inkjet recording apparatus

Technical Field

The present invention relates to an aqueous ink for inkjet recording and an inkjet recording apparatus.

Background

In order to simultaneously suppress clogging of nozzles in an ink jet head and improve drying property on a recording medium, there is proposed an aqueous ink for ink jet recording which comprises a water-soluble solid urea derivative having a melting point of not less than 50 ℃ and a water-soluble liquid urea derivative having a melting point of not more than 10 ℃ (patent document 1).

CITATION LIST

Patent document

[ patent document 1] Japanese patent application laid-open No. H11-228895

Disclosure of Invention

Technical problem

However, in some cases, in an aqueous ink for inkjet recording, depending on the selection of the species of liquid components and solid components and their content ratios, suppression of any nozzle clogging cannot be achieved, and/or the dry state on the recording medium is unsatisfactory.

In view of the above circumstances, an object of the present invention is to provide an aqueous ink for inkjet recording, which is capable of suppressing clogging of nozzles and has a good dry state on a recording medium.

Solution to the problem

According to a first aspect of the present invention, there is provided an aqueous ink for inkjet recording, comprising:

a liquid component that is liquid at 20 ℃; and

a solid component which is solid at 20 ℃,

the liquid component includes:

a first water-soluble organic solvent having a vapor pressure of not less than 7Pa at 20 ℃;

a second water-soluble organic solvent having a vapor pressure of not more than 1Pa at 20 ℃; and

water;

the solid component comprises at least one resin selected from the group consisting of: acrylic resins, maleic ester resins, vinyl acetate resins, carbonate resins, styrene resins, vinyl resins, propylene resins, polyurethane resins, vinyl chloride resins, and copolymer resins thereof; and is

The aqueous ink for inkjet recording satisfies the following conditions (1) and (2):

condition (1): 2 is more than or equal to (A + B + C)/D is less than or equal to 6

Condition (2): 0.2-1 of (B + C)/D

In the conditions (1) and (2),

a: the content (mass%) of the first water-soluble organic solvent in the total amount of the aqueous ink,

b: the content (mass%) of the second water-soluble organic solvent in the total amount of the aqueous ink,

c: the content (% by mass) of a component different from the first water-soluble organic solvent, the second water-soluble organic solvent and water contained in the liquid component in the total amount of the aqueous ink, and

d: content (mass%) of solid component in total amount of water-based ink.

According to a second aspect of the present invention, there is provided an inkjet recording apparatus comprising:

an ink reservoir portion that stores the aqueous ink for inkjet recording of the first aspect, and

and an ink ejection mechanism configured to eject the ink stored in the ink reservoir.

Advantageous effects of the invention

The aqueous ink of the present invention contains a liquid component and a solid component, satisfies the above-described conditions (1) and (2), and can thereby suppress clogging of nozzles and achieve a satisfactory dried state on a recording medium.

Drawings

Fig. 1 is a schematic diagram depicting the configuration of an example of an inkjet recording apparatus of the present invention.

Detailed Description

The aqueous ink for inkjet recording (hereinafter also referred to as "aqueous ink" or "ink" in some cases) of the present invention can be suitably used for inkjet recording onto a recording medium having hydrophobicity such as coated paper, plastic, film, OHP sheet, and the like, but is not limited to or by this use. The water-based ink for inkjet recording of the present invention can also be used, for example, for inkjet recording onto a recording medium other than a hydrophobic recording medium, including, for example, regular paper (plain paper), glossy paper, matte paper, and the like. In the present invention, the term "coated paper" refers to, for example, paper obtained by coating ordinary paper having pulp as a main component with a coating agent, such as high-grade printing paper and medium-grade printing paper. The coating agent is applied to the plain paper to improve the smoothness, whiteness, brightness and the like of the plain paper. The coated paper comprises high-grade coated paper, medium-grade coated paper and the like.

The aqueous ink of the present invention will be described. The aqueous ink of the present invention includes a liquid component that is liquid at 20 ℃ and a solid component that is solid at 20 ℃.

The liquid component includes a first water-soluble organic solvent, a second water-soluble organic solvent, and water. The liquid component may also include a component different from the first water-soluble organic solvent, the second water-soluble organic solvent, and water. Alternatively, the liquid component may consist of only the first water-soluble organic solvent, the second water-soluble organic solvent and water.

The vapor pressure of the first water-soluble organic solvent at 20 ℃ is not less than 7 Pa. Examples of the first water-soluble organic solvent include propylene glycol (hereinafter, may be abbreviated as "PG", vapor pressure at 20 ℃ C.: 10.6Pa), 1, 3-butanediol (vapor pressure at 20 ℃ C.: 8Pa), and ethylene glycol (hereinafter, may be abbreviated as "EG", vapor pressure at 20 ℃ C.: 7 Pa). Each of these water-soluble organic solvents may function as a humectant to prevent the aqueous ink from drying at the tip of the nozzle in the ink-jet head.

Only one of the above-described first water-soluble organic solvents may be used alone, or two or more of the above-described first water-soluble organic solvents may be used in combination. The content (a) of the first water-soluble organic solvent in the total amount of the aqueous ink will be described later.

The vapor pressure of the second water-soluble organic solvent at 20 ℃ is not more than 1 Pa. Examples of the second water-soluble organic solvent include tripropylene glycol (hereinafter, sometimes referred to as "TPG", vapor pressure at 20 ℃ of 0.67Pa), diethylene glycol (hereinafter, sometimes referred to as "DEG", vapor pressure at 25 ℃ of 0.76Pa), glycerin (hereinafter, sometimes referred to as "GLY", vapor pressure at 25 ℃ of 0.01Pa), 1, 5-pentanediol (vapor pressure at 25 ℃ of 0.52Pa), triethylene glycol n-butyl ether (hereinafter, sometimes referred to as "BTG", vapor pressure at 25 ℃ of 0.33Pa), tripropylene glycol n-butyl ether (hereinafter, sometimes referred to as "TPnB", vapor pressure at 20 ℃ of 0.02Pa), and the like. The vapor pressures of DEG, GLY, 1, 5-pentanediol, and BTG described above are indicated at 25 ℃. However, since the vapor pressure of these second water-soluble organic solvents at 20 ℃ is smaller than that at 25 ℃, the vapor pressure of these second water-soluble organic solvents at 20 ℃ does not exceed 1 Pa. Among the second water-soluble organic solvents listed above, TPG, DEG, GLY and 1, 5-pentanediol can function, for example, as humectants. Further, among the second water-soluble organic solvents listed above, BTG and TPnB can be used as, for example, penetrants which regulate the spreading of the aqueous ink on the recording medium and/or the drying speed of the aqueous ink on the recording medium.

The second water-soluble organic solvent may be used alone or in combination of two or more. The content (B) of the second water-soluble organic solvent in the total amount of the aqueous ink will be described later.

The water-soluble organic solvent contained in the aqueous ink may be only the first water-soluble organic solvent and the second water-soluble organic solvent as described above. Further, the aqueous ink may include another water-soluble organic solvent different from the first and second water-soluble organic solvents, in addition to the first and second water-soluble organic solvents.

The water is preferably ion-exchanged water or pure water (purified water). The content of water in the total amount of the aqueous ink is, for example, in the range of 20 to 80% by mass. The water content may be, for example, the balance of the other components.

The solid component comprises at least one resin selected from the group consisting of: acrylic resins, maleic ester resins, vinyl acetate resins, carbonate resins, styrene resins, vinyl resins, propylene resins, polyurethane resins, vinyl chloride resins, and copolymer resins thereof. Only one kind of the above-mentioned resin may be used alone, or two or more kinds of the above-mentioned resins may be used in combination.

The resin may include resin fine particles (resin fine particles). That is, the aqueous ink may contain resin fine particles as a resin. The glass transition temperature (Tg) of the resin fine particles is, for example, 100 ℃ or lower. The resin fine particles may be, for example, resin fine particles contained in a resin emulsion. The term "resin emulsion" refers to a resin emulsion composed of, for example, resin fine particles and a dispersion medium (e.g., water, etc.); in the resin emulsion, the resin fine particles are dispersed in a dispersion medium in a specific particle diameter (size), not in a dissolved state. In the present specification, the resin fine particles contained in the resin emulsion are defined as "emulsion fine particles". The aqueous ink of the present embodiment may contain emulsion microparticles as its solid component. The emulsion particles preferably include an acrylic resin (acrylic resin), a styrene-acrylic resin (copolymer of a styrene-based resin and an acrylic resin), a polyurethane resin (polyurethane-based resin), or a vinyl chloride-acrylic copolymer (copolymer of a vinyl chloride-based resin and an acrylic resin). Only one kind of the above-mentioned emulsion fine particles may be used alone, or two or more kinds of the above-mentioned emulsion fine particles may be used in combination.

As the resin emulsion, for example, a commercially available product can be used. As commercially available products, there are exemplified "MOWINYL (trade name) 6969D" (acrylic resin emulsion) (Tg: 71 ℃ C.), "MOWINYL (trade name) 5450" (Tg: 53 ℃ C.), "MOWINYL (trade name) DM 772" (Tg: 22 ℃ C.); "POLYSOL (trade name) AP-3770 (styrene-acrylic resin emulsion)" manufactured by showa electric works in japan; "SUPERFLEX (trade name) 150" (polyurethane resin emulsion) (Tg: 40 ℃ C.) manufactured by DKS K.K. (first Industrial pharmaceutical Co., Ltd., Japan); VINYBLAN (trade name) 701 (vinyl chloride-acrylic copolymer emulsion) manufactured by rixin chemical industries, ltd.

The average (mean) particle diameter (size) of the resin fine particles is, for example, in the range of 20nm to 300 nm. The average particle diameter may be measured as an arithmetic average diameter, for example, by using a dynamic light scattering particle size distribution measuring apparatus "LB-550" (product name) manufactured by rise corporation, japan. The average particle diameter may be an average particle diameter (intensity average particle diameter) calculated based on a particle diameter distribution of intensity (particle diameter distribution based on light scattering intensity).

The content of the fine resin particles in the total amount of the aqueous ink is, for example, in the range of 1 to 10% by mass. One kind of the above-mentioned fine resin particles may be used alone, or two or more kinds of the above-mentioned fine resin particles may be used in combination.

The aqueous ink may be a colored ink containing a colorant, or may be an achromatic (colorless) ink containing no colorant. In the color ink, the colorant may be any one of a pigment and a dye. Further, as the colorant, a pigment and a dye may be mixed and used as the colorant.

The pigment is not particularly limited, and may be, for example, carbon black, an inorganic pigment, an organic pigment, or the like. Examples of the carbon black include furnace black, lamp black, acetylene black, channel black and the like. Examples of the inorganic pigment include titanium oxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of the organic pigment are, for example, azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.; dye lake pigments such as basic dye type lake pigments, acid dye type lake pigments and the like; nitro pigments; a nitroso pigment; nigrosine daylight fluorescent pigment; and so on. Furthermore, it is also permissible to use, as the pigment, any pigment other than those listed above but dispersible in an aqueous phase. Specific examples of these pigments include, for example, c.i. pigment black 1, 6 and 7; c.i. pigment yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 74, 78, 150, 151, 154, 180, 185 and 194; c.i. pigment orange 31 and 43; c.i. pigment red 2, 3, 5,6, 7, 12, 15, 16, 48:1, 53:1, 57:1, 112, 122, 123, 139, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 209, 221, 222, 224 and 238; c.i. pigment violet 19 and 196; c.i. pigment blue 1, 2, 3, 15:1, 15:2, 15:3, 15:4, 16, 22 and 60; c.i. pigment green 7 and 36; and solid solutions of the above pigments. The aqueous ink of the present invention can be prepared by dispersing a pigment in water with a dispersant. As the dispersant, for example, a general polymer dispersant (a pigment-dispersing resin, a resin-dispersed pigment, a resin dispersant) or the like can be used, and it can be prepared by itself. Alternatively, in the aqueous ink of the present invention, the pigment may also be polymer-encapsulated.

The pigment may be a self-dispersing pigment. The self-dispersible pigment can be dispersed in water without using any dispersant, for example, because at least one hydrophilic functional group and a salt thereof, including, for example, a carbonyl group, a hydroxyl group, a carboxylic acid group, a sulfo group (sulfonic acid group), a phosphoric acid group (phosphoric acid group), or the like, is introduced to the surface of the pigment particle through a chemical bond (directly introduced or having any group therebetween). Self-dispersible pigments surface-treated by any one of methods may be used, for example, japanese patent application publication No. HEI8-3498 (corresponding to U.S. patent No. 5,609,671), PCT international published japanese translation of patent application No. 2000-513396 (corresponding to U.S. patent No. 5,837,045), PCT international published japanese translation of patent application No. 2008-524400 (corresponding to U.S. patent No. US2006/0201380a1), PCT international published japanese translation of patent application No. 2009-515007 (corresponding to U.S. patent No. US2007/0100023a1 and US2007/0100024a1), PCT international published japanese translation of patent application No. 2011-515535 (corresponding to U.S. patent No. 2009/0229489a1), and the like. As a material of the self-dispersible pigment, any of an inorganic pigment and an organic pigment may be used. Further, pigments suitable for the above treatment include, for example, carbon blacks such as "MA 8" and "MA 100" produced by mitsubishi chemical corporation, and the like. As the self-dispersible pigment, a commercially available product can be used, for example. Commercially available products include, for example, "CAB-O-JET (trade name) 200", "CAB-O-JET (trade name) 250C", "CAB-O-JET (trade name) 260M", "CAB-O-JET (trade name) 270Y", "CAB-O-JET (trade name) 300", "CAB-O-JET (trade name) 400", "CAB-O-JET (trade name) 450C", "CAB-O-JET (trade name) 465M", and "CAB-O-JET (trade name) 470Y", which are produced by Cabot specialty chemicals; "BONJET (trade name) BLACK CW-2" and "BONJET (trade name) BLACK CW-3" manufactured by Oriental chemical Co., Ltd.; "LIOJET (trade name) WD BLACK 002C" manufactured by Toyo ink Co., Ltd.; and the like.

The solid content of the pigment (pigment solid content) in the total amount of the aqueous ink is not particularly limited, and may be appropriately determined depending on, for example, a desired optical density, chromaticity, and the like. The amount of the pigment solid component is, for example, in the range of 0.1 to 20 mass%, in the range of 1 to 15 mass%, or in the range of 2 to 10 mass%.

The pigment and the resin for dispersing the pigment (resin dispersant) correspond to the solid component.

The dye is not particularly limited, and examples thereof include direct dyes, acid dyes, basic dyes, reactive dyes, and food dyes. Specific examples of the dye include, for example, c.i. direct black, c.i. direct blue, c.i. direct red, c.i. direct yellow, c.i. direct orange, c.i. direct violet, c.i. direct brown, c.i. direct green; c.i. acid black, c.i. acid blue, c.i. acid red, c.i. acid yellow, c.i. acid orange, c.i. acid violet; c.i. basic black, c.i. basic blue, c.i. basic red, c.i. basic violet; c.i. reaction blue, c.i. reaction red, c.i. reaction yellow; C.I. edible black, C.I. edible red and C.I. edible yellow; and the like. The c.i. direct black described above includes, for example, c.i. direct black 17, 19, 22, 31, 32, 51, 62, 71, 74, 108, 112, 113, 146, 154, 168, 195 and the like. Examples of the c.i. direct blue include c.i. direct blue 1, 6, 15, 22, 25, 41, 71, 76, 77, 80, 86, 90, 98, 106, 108, 120, 158, 163, 168, 199, 226 and the like. Examples of the above-mentioned c.i. direct red include c.i. direct red 1, 2, 4, 9, 11, 17, 20, 23, 24, 28, 31, 39, 46, 62, 75, 79, 80, 83, 89, 95, 197, 201, 218, 220, 224, 225, 226, 227, 228, 229, 230 and the like. Examples of the above-mentioned c.i. direct yellow include c.i. direct yellow 8, 11, 12, 24, 26, 27, 28, 33, 39, 44, 50, 58, 85, 86, 87, 88, 89, 98, 100, 110, 132, 142, 173 and the like. Examples of the above-mentioned c.i. direct orange are c.i. direct oranges 34, 39, 44, 46, 60 and the like. Examples of the above-mentioned c.i. direct violet include c.i. direct violet 47, 48 and the like. Examples of the above-mentioned c.i. direct brown include c.i. direct brown 109 and the like. Examples of the above-mentioned c.i. direct green include c.i. direct green 59 and the like. Examples of the c.i. acid black include c.i. acid black 2, 7, 24, 26, 31, 48, 51, 52, 63, 110, 112, 115, 118, 156 and the like. Examples of the above-mentioned c.i. acid blue include c.i. acid blue 1, 7, 9, 15, 22, 23, 25, 29, 40, 43, 59, 62, 74, 78, 80, 90, 93, 100, 102, 104, 117, 120, 127, 138, 158, 161, 167, 220, 234 and the like. Examples of the above-mentioned c.i. acid red include c.i. acid red 1, 6, 8, 9, 13, 14, 18, 26, 27, 32, 35, 37, 42, 51, 52, 80, 83, 85, 87, 89, 92, 94, 106, 114, 115, 133, 134, 145, 158, 180, 198, 249, 256, 265, 289, 315, 317 and the like. Examples of the above-mentioned c.i. acid yellow include c.i. acid yellow 1,3, 7, 11, 17, 23, 25, 29, 36, 38, 40, 42, 44, 61, 71, 76, 98, 99 and the like. Examples of the above-mentioned c.i. acid orange include c.i. acid orange 7, 19 and the like. Examples of the above-mentioned c.i. acid violet include c.i. acid violet 49 and the like. Examples of c.i. basic black include c.i. basic black 2 and the like. Examples of c.i. basic blue are c.i. basic blue 1,3, 5, 7, 9, 24, 25, 26, 28, 29, etc. Examples of c.i. basic red include c.i. basic red 1, 2, 9, 12, 13, 14, 37, and the like. Examples of c.i. basic violet are c.i. basic violet 7, 14, 27 etc. Examples of the above-mentioned c.i. reactive blue include c.i. reactive blue 4, 5, 7, 13, 14, 15, 18, 19, 21, 26, 27, 29, 32, 38, 40, 44, 100 and the like. Examples of the above-mentioned c.i. reaction red include c.i. reaction red 7, 12, 13, 15, 17, 20, 23, 24, 31, 42, 45, 46, 59 and the like. Examples of the above-mentioned c.i. reactive yellow include c.i. reactive yellow 2, 3, 17, 25, 37, 42 and the like. Examples of the c.i. food black include c.i. food blacks 1 and 2. Examples of the above-mentioned c.i. food red include c.i. food red 87, 92, 94 and the like. Examples of the c.i. edible yellow include c.i. edible yellow 3 and the like.

The above dyes may be used singly or in combination of two or more. The content of the dye in the total amount of the aqueous ink is, for example, in the range of 0.1 to 20 mass%, in the range of 1 to 15 mass%, or in the range of 2 to 10 mass%. The dye corresponds to the solid component.

The aqueous ink may further include conventionally known additives as needed. Examples of the additives include a pH adjuster, a viscosity adjuster, a surface tension adjuster, and a bactericide. Examples of the viscosity modifier include polyvinyl alcohol, cellulose, and water-soluble resins. The additives which are liquid (in liquid state) at 20 ℃ correspond to the above-mentioned liquid components. The content (C) of the component different from the first water-soluble organic solvent, the second water-soluble organic solvent and water contained in the liquid component will be described later. The aqueous ink may include a surfactant that is liquid (in a liquid state) at 20 ℃. Further, the additive which is solid (solid state) at 20 ℃ corresponds to the above solid component. The aqueous ink may include a surfactant that is solid at 20 ℃.

The aqueous ink can be prepared, for example, as follows: the liquid component, the solid component and, as necessary, other additives are uniformly mixed by a conventionally known method, and then any insoluble matter is removed with a filter or the like.

The aqueous ink satisfies the following conditions (1) and (2). The aqueous ink contains a liquid component, a solid component to satisfy the following conditions (1) and (2), whereby it is possible to suppress any clogging of nozzles and achieve a satisfactory dry state on a recording medium, and further improve the flexibility and spreadability, scratch resistance (rubbing or abrasion resistance), and blocking property of a recorded article (recorded matter).

Condition (2): 0.2-1 of (B + C)/D

Wherein in the conditions (1) and (2),

d: content (mass%) of solid component in total amount of water-based ink.

The content (a) of the first water-soluble organic solvent (mass%), the content (B) of the second water-soluble organic solvent (mass%), the content (C) of a component different from the first water-soluble organic solvent, the second water-soluble organic solvent and water contained in the liquid component (mass%) and the content (D) of the solid component (mass%) may be appropriately adjusted to satisfy the above-described conditions (1) and (2).

The aqueous ink preferably satisfies the following condition (3). By satisfying the condition (3), the aqueous ink can suppress clogging of nozzles and achieve a satisfactory dried state on a recording medium, and further improve the flexibility and spreadability, scratch resistance (rubbing resistance or abrasion resistance), and blocking property of a recorded article (recorded matter).

Condition (3): a + B is more than or equal to 10 and less than or equal to 40

Wherein in the condition (3) above,

a: the content (% by mass) of the first water-soluble organic solvent in the total amount of the aqueous ink, and

b: the content (mass%) of the second water-soluble organic solvent in the total amount of the aqueous ink.

Further, the ratio (A/B) of the content (A: mass%) of the first water-soluble organic solvent in the total amount of the aqueous ink to the content (B: mass%) of the second water-soluble organic solvent in the total amount of the aqueous ink is preferably in the range of 1 to 30. By making the ratio (a/B) in the range of 1 to 30, nozzle clogging can be suppressed, the recording medium can be brought into a satisfactory dry state, and the flexibility and spreadability, scratch resistance, and blocking property of the recorded matter are further improved.

In the condition (1), (a + B + C) is a content (mass%) of a component other than water contained in the liquid component in the total amount of the aqueous ink. In the case where the ratio of the content of the component other than water to the solid component contained in the liquid component ((a + B + C)/D) is large, the possibility of occurrence of clogging of the nozzle is small. On the other hand, in the case where the ratio ((a + B + C)/D) of the content of the component other than water contained in the liquid component to the solid component is small, the drying of the recording medium can be promoted. Therefore, when the value of (A + B + C)/D is not less than 2, clogging of the nozzle can be suppressed. On the other hand, in the case where the value of (a + B + C)/D is not more than 6, a satisfactory dried state can be achieved on the recording medium.

In addition, when the value of (A + B + C)/D is not less than 3, clogging of the nozzle can be further suppressed. On the other hand, in the case where the value of (a + B + C)/D is not more than 5, a more satisfactory dried state can be achieved on the recording medium. Therefore, the aqueous ink more preferably satisfies the following condition (4). By satisfying the condition (4), the aqueous ink can further suppress clogging of the nozzles and achieve a more satisfactory dried state on the recording medium.

Condition (4): 3 is more than or equal to (A + B + C)/D is less than or equal to 5

Wherein in the condition (4) above,

d: content (mass%) of solid component in total amount of water-based ink.

In the condition (2), (B + C) is a content (mass%) of a component different from the water and the first water-soluble organic solvent contained in the liquid component in the total amount of the aqueous ink. In the case where the ratio ((B + C)/D) of the content of the component different from the water and the first water-soluble organic solvent to the solid component contained in the liquid component is large, then the image of the recorded matter is less likely to be disturbed even in the case where the image recorded on the recorded matter is curved. That is, the flexibility and spreadability of the recorded matter can be made satisfactory. On the other hand, in the case where the ratio ((B + C)/D) of the content of the component other than water and the first water-soluble organic solvent to the solid component contained in the liquid component is small, the scratch resistance and blocking property of the recorded matter are enhanced. Therefore, in the case where the value of (B + C)/D is not less than 0.2, the flexibility and spreadability of the recorded matter can be enhanced. On the other hand, in the case where the value of (B + C)/D is not more than 1.0, the scratch resistance and blocking property of the recorded matter are enhanced.

Further, in the case where the value of (B + C)/D is not less than 0.3, the flexibility and spreadability of the recorded matter can be further enhanced. Further, in the case where the value of (B + C)/D is not more than 0.8, the scratch resistance and blocking property of the recorded matter can be further enhanced. Therefore, the aqueous ink more preferably satisfies the following condition (5). By satisfying the condition (5), the aqueous ink can further improve the flexibility and spreadability of the recorded matter, and further improve the scratch resistance and blocking property of the recorded matter.

Condition (5): (B + C)/D is more than or equal to 0.3 and less than or equal to 0.8

Wherein in the condition (5) above,

d: content (mass%) of solid component in total amount of water-based ink.

Next, the inkjet recording apparatus and inkjet recording method of the present invention will be explained.

An inkjet recording apparatus of the present invention is an inkjet recording apparatus characterized by comprising: an ink reservoir and an ink ejection mechanism (ink ejection mechanism); and configured to eject the ink stored in the ink reservoir by the ink ejection mechanism; wherein the aqueous ink for inkjet recording of the present invention is stored in an ink reservoir. As will be described later, the inkjet recording apparatus of the present invention may further include a drying mechanism configured to dry a recording member or a recording portion recorded by using ink.

The inkjet recording method of the present invention is characterized by comprising a recording step of performing recording on a recording medium by ejecting (jetting) an aqueous ink onto the recording medium according to an inkjet system; among them, the aqueous ink for inkjet recording of the present invention is used as an aqueous ink in a recording step. The inkjet recording method of the present invention may further include a fixing step of fixing the aqueous ink to the recording medium by using a drying mechanism configured to dry a recording portion of the recording medium.

The inkjet recording method of the invention can be carried out, for example, using the inkjet recording apparatus of the invention. The recording includes printing text (text), printing images, printing, and the like.

Fig. 1 schematically depicts an exemplary configuration of an inkjet recording apparatus of the present invention. As shown in fig. 1, the inkjet recording apparatus 100 includes a feed tray 101, a conveying mechanism (not shown) such as a roller,

recording mechanisms

102A and 102B, a platen 103, a drying mechanism 104, a discharge tray 105, and an ink reservoir (not shown), such as an ink cartridge or an ink tank. The feed tray 101 may support a plurality of recording media P (e.g., a plurality of coated papers) stacked thereon.

The recording mechanism includes a carriage 102A and an inkjet head (inkjet mechanism) 102B. The carriage 102A is supported by two guide rails (not depicted) extending perpendicularly with respect to the conveying direction of the recording medium P. These two guide rails are supported by a housing (not depicted) of the inkjet recording apparatus 100. The carriage 102A is connected to a well-known belt conveying mechanism (not shown) provided in two guide rails. The belt conveying mechanism is driven by a carriage motor (not shown). The carriage motor is driven to reciprocate (reciprocate) the carriage 102A connected to the belt conveying mechanism in an orthogonal direction orthogonal to the conveying direction of the recording medium P.

Further, four ink tubes (not shown) connecting the ink reservoir and the inkjet head 102B, and a flexible flat cable (not shown) electrically connecting a control board (not shown) and the inkjet head 102B extend from the carriage 102A. The aqueous inks of four colors (yellow, magenta, cyan, and black) stored in the ink tanks are supplied to the inkjet head 102B via four ink tubes. At least one of the four aqueous inks is the aqueous ink for inkjet recording of the present invention. The control signal outputted from the control board is transmitted to the ink jet head 102B through the flexible flat cable.

As shown in fig. 1, the carriage 102A has an inkjet head 102B mounted or mounted therein. A plurality of nozzles 102C are formed in the lower surface of the inkjet head 102B. A front end of each of the plurality of nozzles 102C is exposed from the lower surfaces of the carriage 102A and the inkjet head 102B. The inkjet head 102B includes an actuator (not depicted) that applies a force for ejecting the aqueous ink supplied from the ink tank to the inkjet head 102B via the ink tubes. The actuator may be any system of actuators such as a piezoelectric element system, a thermal inkjet system, an electrostatic attraction system, and the like. The inkjet head 102B ejects or discharges the aqueous ink from the plurality of nozzles 102C in the form of fine or minute ink droplets in the process in which the carriage 102A reciprocates in the direction orthogonal to the conveyance direction of the recording medium P. Thereby, an image is recorded on the recording medium P. The inkjet recording apparatus 100 may have a cap (not depicted) that covers the plurality of nozzles 102C of the inkjet head 102, and the inkjet head 102 returns to the rest position in the case where recording is completed. The platen 103 is arranged to face the recording mechanism, and supports the recording medium P conveyed from the feed tray 101.

The drying mechanism 104 heats and dries the recording portion of the recording medium P. The drying temperature during drying can be appropriately adjusted by changing the setting of the drying mechanism 104. Specifically, the drying temperature may be, for example, in the range of 20 ℃ to 200 ℃ or in the range of 50 ℃ to 100 ℃. The drying time can also be adjusted appropriately by changing the setting of the drying mechanism 104. For example, the drying time may be in the range of more than 0 (zero) seconds to no more than 300 seconds, in the range of 0.1 seconds to 60 seconds, or in the range of 30 seconds to 60 seconds. Any drying mechanism capable of drying the recording portion may be used as the drying mechanism 104. Examples of drying mechanism 104 include, for example, a heating mechanism such as a commercially available dryer, an IR heater, an oven, a conveyor oven, an iron, a hot press, and the like. It is preferable to use a non-contact drying mechanism such as a dryer, an oven, a conveyor-type oven, or the like, which dries the recording portion of the recording medium P without contacting the recording portion.

The recording medium P after recording and drying is conveyed to the discharge tray 105.

Examples

Next, examples of the present invention will be described together with comparative examples. Note that the present invention is not limited to the examples and comparative examples described below.

< preparation of Black pigment Dispersion >

135g of Terathane (trade name) 650 (polyether glycol produced by Envyda corporation (Wickta, KS)), 54g of 2,2' -dimethylolpropionic acid (DMPA), 132g of sulfolane and 0.06g of dibutyltin dilaurate (DBTDL) were charged into a flask equipped with a dropping funnel, a condenser and a stirrer (stirring device) under a nitrogen atmosphere, heated to 60 ℃ while mixing, and thoroughly mixed, thereby obtaining a mixture. To the resulting mixture was added 164g of m-Tetramethylenexylylenediisocyanate (TMXDI) using a dropping funnel, and the remaining TMXDI in the dropping funnel was rinsed into the flask with 15g of sulfolane. The temperature was raised to 100 ℃ and the temperature was maintained at 100 ℃ until the isocyanate content reached 1.3% by mass or less. Subsequently, the temperature was decreased to 60 ℃, and then 12.9g of Diethanolamine (DEA) was added to the mixture over 5 (five) minutes using a dropping funnel, and the temperature was maintained at 60 ℃ until the remaining DEA in the dropping funnel was washed into the flask with 5g of sulfolane. The temperature was further maintained at 60 ℃ for one hour, and then 376g of a 3 mass% aqueous potassium hydroxide solution was added to the mixture over 10 (ten) minutes using a dropping funnel, followed by 570g of deionized water to the mixture. Then, the mixture was incubated at 60 ℃ for 1 hour and cooled to room temperature. Thereby, a resin dispersant having a solid content of 24 mass% was obtained.

< preparation of Black pigment Dispersion >

The resin dispersant is neutralized with potassium hydroxide to increase the solubility in water, so that the resin dispersant is easily soluble in water. Then, a microfluidizer (model name: M-110Y, manufactured by microfluidics international corporation, massachusetts) of a high-pressure compressed air system was used to prepare a mixture in which the content of carbon black (c.i. pigment black 7) was about 27 mass%, and the mass ratio (P/D) of the content of carbon black (P) to the content of resin dispersant (D) was P/D3. Then, deionized water was added to the mixture so that the content of carbon black was about 24 mass% to be suitable for the medium-mill grinding conditions; and the mixture was milled (pulverized) for 4 (four) hours. After grinding, deionized water was added, the mixture was thoroughly mixed, filtered to remove impurities, and diluted with deionized water so that the content of carbon black became 15 mass%, thereby obtaining a black pigment dispersion.

< preparation of blue pigment Dispersion >

The resin dispersant is neutralized with potassium hydroxide to increase the solubility in water, so that the resin dispersant is easily soluble in water. Then, an Eiger Minimill (model name: M250, manufactured by VSE EXP, Eiger machine INC (chicago, illinois)) of a bead mill system was used to prepare a mixture in which the content of the blue pigment (c.i. pigment blue 15:3) was about 27 mass%, the mass ratio (P/D) of the content (P) of the blue pigment to the content (D) of the resin dispersant was P/D ═ 3, then, deionized water was added to the mixture so that the content of the blue pigment was about 18 mass% to be suitable for the medium mill grinding conditions, and the mixture was ground (pulverized) for 4 (four) hours, then, deionized water was added, after the mixture was sufficiently mixed, after impurities were filtered off, diluted with deionized water so that the content of the blue pigment was 15 mass%, thereby obtaining a blue pigment dispersion.

< preparation of blue pigment Dispersion >

A red pigment dispersion liquid was obtained similarly to the preparation system of the blue pigment dispersion liquid described above, except that a red pigment (c.i. pigment red 122) was used instead of the blue pigment.

< preparation of yellow pigment Dispersion >

The resin dispersant is neutralized with potassium hydroxide to increase the solubility in water, so that the resin dispersant is easily soluble in water. Then, an Eiger Minimill (model name: M250, manufactured by VSE EXP, Eiger machine INC (chicago, illinois)) of a bead mill system was used to prepare a mixture in which the content of the yellow pigment (c.i. pigment yellow 74) was about 30 mass%, the mass ratio (P/D) of the content (P) of the yellow pigment to the content (D) of the resin dispersant was P/D ═ 5.

< examples 1 to 7 and 9 and comparative examples 1 to 4>

Mixing the components or ingredients except the pigment dispersion liquid in the aqueous ink composition (table 1) uniformly or homogeneously; thereby obtaining an ink solvent. Subsequently, an ink solvent is added to the pigment dispersion liquid, followed by uniform mixing, thereby obtaining a mixture. Thereafter, the resulting mixture was filtered through a cellulose acetate membrane filter (pore diameter 3.00 μm) produced by Toyo Filter paper Co., Ltd, to thereby obtain each of the aqueous inks for inkjet recording of examples 1 to 7 and 9 and comparative examples 1 to 4 as shown in Table 1.

< example 8>

Mixing the components or ingredients except the pigment dispersion liquid in the aqueous ink composition (table 1) uniformly or homogeneously; thereby obtaining a mixture. Thereafter, the resulting mixture was filtered through a Polytetrafluoroethylene (PTFE) membrane filter (pore size 0.20 μm) produced by toyoyo filter paper co., ltd., to obtain the aqueous ink for inkjet recording in example 8, as shown in table 1. The aqueous ink of example 8 is an achromatic or achromatic ink (solid ink) containing no colorant.

With respect to the water-based inks of examples 1 to 9 and comparative examples 1 to 4, (a) evaluation of nozzle clogging, (b) evaluation of drying property, (c) evaluation of flexibility and spreadability, and (d) evaluation of scratch resistance and blocking property were performed by the following methods.

(a) Nozzle clogging evaluation

After an inkjet printer MFC-J4225N produced by brother industries co., ltd was left for a predetermined period of time with its inkjet head uncapped, the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 were ejected from the inkjet printer MFC-J4225N, and clogging of the nozzles was evaluated according to the following evaluation criteria.

< evaluation of nozzle clogging: evaluation criteria >

AA: the ejection of the aqueous ink from the ink jet head left standing for 30 (thirty) minutes in an uncapped state was not problematic.

A: although there was a problem with the ejection of the aqueous ink from the inkjet head which was left to stand in the uncapped state for 30 (thirty) minutes, there was no problem with the ejection of the ink from the inkjet head which was left to stand in the uncapped state for 15 (fifteen) minutes.

B: there was a problem in that the aqueous ink was ejected from the ink jet head left to stand in an uncapped state for 15 (fifteen) minutes.

(b) Evaluation of drying Property

An image was recorded on coated paper (product name: "OK Top Coat Plus" manufactured by Wangzi paper Co., Ltd.) using each of the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 using the above-mentioned ink jet printer MFC-J4225N. Each of the images recorded using one of the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 was dried while changing the drying conditions, and the quick-drying property was evaluated according to the following evaluation criteria.

< evaluation of drying property: evaluation criteria >

AA: the aqueous ink was dried at a temperature of 100 ℃ and a drying time of 60 (sixty) seconds.

A: although the aqueous ink was not dried under the conditions of the temperature of 100 ℃ and the drying time of 60 (sixty) seconds, the aqueous ink was dried under the conditions of the temperature of 100 ℃ and the drying time of 120 (one hundred twenty) seconds.

B: the aqueous ink did not dry at a temperature of 100 ℃ and a drying time of 120 (one hundred twenty) seconds.

(c) Evaluation of flexibility and spreadability

An image was recorded on coated paper (product name: "OK Top Coat Plus" produced by king-son paper company) using each of the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 using the above-described inkjet printer MFC-J4225N to obtain a recorded matter having an image recorded thereon. Each of the recorded matters using one of the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 was bent, and flexibility and spreadability were evaluated according to the following evaluation criteria.

< evaluation of flexibility and spreadability: evaluation criteria >

AA: even in the case where the recorded matter is curved, the image is not disturbed.

A: in the case where the recorded matter was bent, although the aqueous ink was not peeled (separated) from the recorded matter, a slightly broken portion was observed.

B: in the case where the recorded matter was bent, slight peeling (separation) of part of the aqueous ink from the recorded matter was observed.

(d) Scratch resistance and adhesion evaluation

An image was recorded on coated paper (product name: "OK Top Coat Plus" produced by king-son paper company) using each of the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 using the above-described inkjet printer MFC-J4225N to obtain a recorded matter having an image recorded thereon. The recorded matter recorded using one of the aqueous inks of examples 1 to 9 and comparative examples 1 to 4 was touched with a finger, and the scratch resistance and blocking property were evaluated according to the following evaluation criteria.

< evaluation of scratch resistance and blocking property: evaluation criteria >

AA: even when the image on the recorded matter was touched with a finger, there was no sticky feeling.

A: when the image on the recorded matter was touched with a finger, the aqueous ink was not transferred to the finger although the image was slightly sticky.

B: when an image on a recorded matter is touched with a finger, the ink had a sticky feeling and the water-based ink was slightly transferred to the finger.

The aqueous ink compositions of examples 1 to 9 and comparative examples 1 to 4 and the evaluation results of the above evaluations (a) to (d) are shown in the following table 1.

TABLE 1 (below) -legend

*1: acrylic resin emulsion produced by Nippon paint resin Co., Ltd; the numbers in table 1 represent the effective component amounts (solid component amounts);

*2: styrene-acrylic resin emulsion produced by Showa Denko K.K.; the numbers in table 1 represent the effective component amounts (solid component amounts);

*3: a polyurethane resin emulsion produced by first industrial pharmaceutical co; the numbers in table 1 represent the effective component amounts (solid component amounts);

*4: vinyl chloride-acrylic copolymer emulsion produced by Nissin chemical industries, Ltd; the numbers in table 1 represent the effective component amounts (solid component amounts);

*5: nonionic surfactants (liquid at 20 ℃) produced by Nisin chemical industries, Ltd, the numbers in Table 1 represent the amounts of active ingredients;

*6: nonionic surfactant (solid at 20 ℃) produced by Kao corporation, the numerals in Table 1 represent the amounts of active ingredients;

*7: the numbers listed in Table 1 represent the amount of pigment solids;

*8: the numbers listed in Table 1 represent the amount of pigment solids;

*9: the numbers listed in Table 1 represent the amount of pigment solids; and

*10: the numbers in the upper column of Table 1 indicate the amount of the solid components of the pigment.

TABLE 1

Table 1 (continuation watch)

Table 1 (continuation watch)

As shown in table 1, in examples 1 to 9 satisfying conditions (1) and (2), all the evaluation results with respect to (a) nozzle clogging, (b) drying property, (c) flexibility and spreadability, and (d) scratch resistance and blocking property were satisfactory. Examples 1 to 9 satisfy the condition (3) and the ratio (a/B) in each of examples 1 to 9 is in the range of 1 to 30.

Further, in examples 1 and 6 to 9 satisfying the conditions (3) and (4), all the evaluation results with respect to (a) nozzle clogging, (b) drying property, (c) flexibility and spreadability, and (d) scratch resistance and blocking property were satisfactory.

On the other hand, comparative example 1 in which (A + B + C)/D < 2 and (B + C)/D < 0.2 and the above conditions (1) and (2) were not satisfied had unsatisfactory results in the evaluations of (a) nozzle clogging and (C) flexibility and spreadability. Further, comparative example 2 in which (a + B + C)/D < 2 and (B + C)/D > 1 and the above conditions (1) and (2) were not satisfied had unsatisfactory results in the evaluation of (a) nozzle clogging and (D) scratch resistance and blocking property. Further, comparative example 3 in which (A + B + C)/D > 6 and (B + C)/D > 1 and the above-described conditions (1) and (2) were not satisfied had unsatisfactory results in the evaluations of (B) drying property and (D) scratch resistance and blocking property. Further, comparative example 4, in which (A + B + C)/D > 6 and (B + C)/D < 0.2 and the above conditions (1) and (2) were not satisfied, had unsatisfactory results in the evaluations of (B) drying property and (C) flexibility and spreadability.

Some or all of the above-described embodiments and examples can also be described in the following appendix. However, the present invention is not limited to the following appendix.

(appendix 1) an aqueous ink for inkjet recording, comprising:

a liquid component that is liquid at 20 ℃; and

a solid component which is solid at 20 ℃,

the liquid component includes:

water;

the solid component comprises at least one resin selected from the group consisting of: acrylic resins, maleic ester resins, vinyl acetate resins, carbonate resins, styrene resins, vinyl resins, propylene resins, polyurethane resins, vinyl chloride resins, and copolymer resins thereof; and

Condition (2): 0.2-1 of (B + C)/D

In the conditions (1) and (2),

d: content (mass%) of solid component in total amount of water-based ink.

(appendix 2) the aqueous ink for inkjet recording according to appendix 1, wherein the first water-soluble organic solvent includes at least one selected from the group consisting of: propylene glycol, 1, 3-butylene glycol and ethylene glycol; and is

The second water-soluble organic solvent includes at least one selected from the group consisting of: tripropylene glycol, diethylene glycol, glycerol, 1, 5-pentanediol, triethylene glycol n-butyl ether, and tripropylene glycol n-butyl ether.

(appendix 3) the aqueous ink for inkjet recording according to appendix 1 or 2, further satisfying the following condition (3):

condition (3): a + B is more than or equal to 10 and less than or equal to 40

In the case of the condition (3),

(appendix 4) the aqueous ink for inkjet recording according to any one of appendices 1 to 3, wherein the aqueous ink contains resin fine particles as the at least one resin.

(appendix 5) the aqueous ink for inkjet recording according to any one of appendices 1 to 4, wherein the aqueous ink further includes a colorant.

(appendix 6) the inkjet recording apparatus includes: an ink reservoir storing the aqueous ink for inkjet recording described in any one of appendices 1 to 5, and an ink ejection mechanism configured to eject the ink stored in the ink reservoir.

(appendix 7) the inkjet recording apparatus according to appendix 6, wherein the inkjet recording apparatus further includes a drying mechanism configured to dry a recording portion recorded by the ink.

(appendix 8) an inkjet recording method including ejecting the aqueous ink described in any one of appendices 1 to 5 onto a recording medium by an inkjet system.

(appendix 9) the inkjet recording method according to appendix 8, wherein the method further comprises fixing the aqueous ink onto the recording medium by using a drying mechanism configured to dry a recording portion of the recording medium.

Industrial applicability

As described above, the aqueous ink of the present invention can suppress clogging of the nozzles and has a good dry state on the recording medium. The use of the aqueous ink of the present invention is not particularly limited to ink jet recording on a hydrophobic recording medium such as coated paper, and can be widely applied to ink jet recording on various recording media, for example, regular paper (plain paper), glossy paper, matte paper, and the like.

REFERENCE SIGNS LIST

100 ink jet recording apparatus

101 feed tray

102A carriage

102B ink jet head (ink ejection mechanism)

102C nozzle

103 pressing plate

104 drying mechanism

105 discharge tray

Claims

1. An aqueous ink for inkjet recording, comprising:

a liquid component that is liquid at 20 ℃; and

a solid component which is solid at 20 ℃,

the liquid component includes:

water;

Condition (2): 0.2-1 of (B + C)/D

In the conditions (1) and (2),

d: content (mass%) of the solid component in the total amount of the aqueous ink.

2. The aqueous ink for inkjet recording according to claim 1, wherein the first water-soluble organic solvent includes at least one selected from the group consisting of: propylene glycol, 1, 3-butylene glycol and ethylene glycol; and

3. The aqueous ink for inkjet recording according to claim 1 or 2, wherein the aqueous ink further satisfies the following condition (3):

condition (3): a + B is more than or equal to 10 and less than or equal to 40

In the case of the condition (3),

4. The aqueous ink for inkjet recording according to any one of claims 1 to 3, wherein the aqueous ink contains resin fine particles as the at least one resin.

5. The aqueous ink for inkjet recording according to claim 4, wherein the resin fine particles are emulsion fine particles.

6. The aqueous ink for inkjet recording according to claim 5, wherein the emulsion microparticles include at least one selected from the group consisting of: acrylic resins, styrene-acrylic resins, polyurethane resins, and vinyl chloride-acrylic copolymers.

7. The aqueous ink for inkjet recording according to any one of claims 1 to 6, wherein the aqueous ink further contains a colorant.

8. The aqueous ink for inkjet recording according to any one of claims 1 to 6, wherein the aqueous ink contains no colorant.

9. The aqueous ink for inkjet recording according to any one of claims 1 to 8, wherein the aqueous ink further satisfies the following condition (4):

condition (4): 3 is less than or equal to (A + B + C)/D5

In the case of the condition (4),

10. The aqueous ink for inkjet recording according to any one of claims 1 to 9, wherein the aqueous ink further satisfies the following condition (5):

In the case of the condition (5),

11. The aqueous ink for inkjet recording according to any one of claims 1 to 10, wherein a ratio (a/B) of a content (a) of the first water-soluble organic solvent in the total amount of the aqueous ink to a content (B) of the second water-soluble organic solvent in the total amount of the aqueous ink is in a range of 1 to 30.

12. An ink jet recording apparatus comprising:

an ink reservoir storing the aqueous ink for inkjet recording of any one of claims 1 to 11, and

an ink ejection mechanism configured to eject the aqueous ink stored in the ink tank.

13. The inkjet recording apparatus according to claim 12, wherein the inkjet recording apparatus further comprises a drying mechanism configured to dry a recording portion recorded by the aqueous ink.